Kinetic models of plasma apoproteins, cholesterol and triglyceride are being constructed based on data from experiments in man. The models are used to integrate plasma liproprotein interactions with enzymes and receptors and to provide a better understanding of plasma liproprotein synthesis and metabolism in health and disease. The models are particularly useful for the rigorous testing of hypotheses, the design of experiments, and the quantification of the effects of various perturbations.